Di-halogen substituted alpha-(p-hydroxyphenyl)-alpha-amino-acetic acid, hydrohalides of the same, and processes for their production



Patented June 29, 1937 PATENT FFEQE DE HALOGEN SUBSTITUTED a- (p-HY- IZ-EZQXYPHENYL) a-ALMINO-ACETIC ACID, HYDROHALIDES OF THE SAME, AND PROCESSES FOR THEIR PRODUCTION No Drawing.

6 Claims.

Our invention relates to antithyroidic compounds, and more particularly to compounds for use in counteracting abnormally increased basal metabolism.

Material increase in basal metabolism, a manifestation of Basedows disease, results in rapid loss of weight, which often proves fatal, if left untreated. Basedows disease is caused by hyperfunction of the thyroid gland, and its treatment is based on prevention of increase in basal metabolism.

Previous to our invention, di-iodo-tyrosine and dibromotyrosine were used in the treatment of Basedows disease, but their antithyroidic effect was relatively low compared with the new compounds which constitute our invention.

It is, therefore, an object of our invention to provide compounds which, when administered in the proper manner, will tend to prevent increase in basal metabolism.

Some time ago, it was pointed out that di-iodotyrosine, which had thus far been regarded as having hypermetabolic action similar to thyroxin, the hormone of the thyroid gland, was really hypometabolic when given in small doses. Dibromtyrosine acts in a similar manner. These two substances have, in the meantime, proved beneficial in the treatment of Basedows disease.

Small quantities of di-iodo-tyrosine occur naturally in the thyroid gland. Chemically, and probably genetically, as well, it is closely related to thyroxin and can, according to its physiological function, be regarded as an antagonist of thyroxin. Since the dibromo compound of tyrosine had also proved effective, indicating that the action appears to be linked with the tyrosine molecule, other iodine and bromine derivatives of tyrosine were prepared. However, pharmacological tests showed that the monobromotyrosine and the bromo-iodo-tyrosine (the latter thus far unknown) were without effect upon artificially increased basal metabolism.

It is, therefore, quite surprising that the iodo and bromo compounds respectively, of oc-(D-hY- droxyphenyl)-a-amino-acetic acid, prepared according to the present invention, show an antithyroidic effect not only equal to, but considerably exceeding that, of di-iodo-tyrosine.

It is notable that the primary substance for these new halogen compounds of :x- (p-hydroxyphenyl) -o-amino-acetic acid does not occur naturaily in the organism and presents an unphysiological grouping in the molecule (phenyl radical and amino groups in a-pOSitlOH to each other). It was not expected that such unphysio- Application July 10, 1934, Serial in Germany August 23, 1933 logical compositions would have an antithyroidio effect, and still less to be expected that they would be more effective than the other known substances, some of which occur naturally.

3,5 dibromo-and 3, 5 di-lOdO-oc-(IJ-hYdIOXYDhG- nyl)-eamino-acetic acid are compounds thus far unknown, which decompose at 204 and 207 C., respectively, when slowly heated, and split off halides. Their compositions correspond to the formulae:

Table Increase in basal metabolism 50 mg. mg.

Percent Percent Controls +25 +30 Di-iodo-tyrosine. +20 +16 Dibr0mo-tyrosine +19 +10 Dl-lOdO-a- (p-hy lroxyphenyl)-a-amino-ace tic aci 2 +3 Dibromo v. -(p-hydroxyphenyl) a aminoacetic acid +11 +4 The superiority of the new compounds over the old ones is quite apparent.

The new group of compounds were obtained by treating a-(p-hydroxyphenyl) o: amino acetic acid with such a quantity of halogenating agent that two atoms thereof are introduced into the phenyl radical. It was found that halogenation may easily be performed, and, therefore, the ordinary methods described in literature will serve the general purpose.

Nevertheless, it was found that especially pure products can be obtained with smooth reaction, if the halogenation is carried out in solutions made alkaline with sodium carbonate or bicarbonate, or in solutions of corresponding alkalinity. Weak alkalinity can, of course, also be The yield is about 5 grams.

attained by adding alkali gradually during the reaction. It was found also that the hydrochlorides, as well as hydrobromides of the new compounds, crystallize out of the acidula'ted reaction solution in a comparatively pure condition and are suitable for immediate further purification by ordinary means.

Example 1 grams of oc-(P-hYdIOXYDhfBIlYI)-ocalmi1'10- acetic acid are dissolved in 100 cc. 2 n-soda solution and agitated with 7.6 grams of powdered iodine until a clear solution is obtained (about 19 min). After the decoloration with charcoal, the solution is run into briskly agitated 10% hydrochloric acid. After a short time, the hydrochloride crystallizes out (-60 grams) and can easily be converted into the free amino acid. The product occurs as a white powder of slightly bitter taste; the melting point is about 205 C., with decomposition.

Example 2 5 grams of a-(p-hydroxyphenyl)flit-aminoacetic acid are dissolved in about cc. diluted alkali solution and gradually 10 grams of iodine monochloride are added. The precipitation is completed with the addition of acetic acid. 1.1. e yield is about 7 grams of crude (ii-iGdO-cc- (p-hydroxyphenyl)x-amino-acetic acid which can be purified by "re-precipitation, for instance. with acetic acid from the ammoniacal solution, or by recrystallization, for instance, from diluted alcohol or diluted acetic acid, or through conversion into the hydrochloride.

Example 3 5 grams of a-(p-hydroxyphenyl) -a-aminoacetic acid are dissolved in about 100 cc. alkali solution and 15.3 grams of powdered iodine added gradually while cooling. After standing for several hours, the solution is acidulated. The crude yield is about 8 grams. Purification as above.

Example 4 5 grams of ov-(D-hYdlOXYDhEnYI)flan-2.1111110- acetic acid are dissolved in about 100 cc. dilute-d hydrochloric acid, adding 10 grams of iodine monochloride in several portions. After prolonged standing, the precipitate is separated. Purification as above' Example 5 2.5 grams oc-(D-hYdIOXYDhGHYI) 0c aminoacetic acid in 100 com. of 10% soda solution is shaken up with 7.6 grams of powdered iodine until solution has been effected, and then filtered after short treatment with animal charcoal, and the reaction liquid is then poured into 100 com. of 11% solution of hydroiodic acid. The hydroiodide of di-iodo a-p-hydroxyphenyl) x-aminoacetic acid is precipitated out. It melts under decomposition at -194: C.

Example 6 8.4 grams of a-(p-hydroxyphenyl)-a-aminoacetic acid are suspended in glacial acetic acid and a solution of 16 grams of bromine in glacial acetic acid added. After heating for 1 hour, the solution is allowed to cool, whereby the hydrobromide will crystallize out. The yield is 13-15 grams. By recrystallization from water, the hydrobromide is purified; from it, the free amino acid is obtained in fine needles by the addition of sodium acetate to its aqueous solution.

Obviously, the various steps of the process may be modified considerably with respect to the order and the number of steps and the specific materiais used in the several methods, without departing from the spirit of the invention substantially as described and claimed, and it is understood that we do not desire to limit ourselves to the specific embodiments shown in the foregoing examples.

We claim as our invention:-

1. In a process for producing di-halogen substituted a (p hydroxyphenyl) a amino acetic acid, the step which comprises reacting upon e--(p-hydroxyphenyl)-u-arnino-acetic acid with a halogenating agent, said halogenating agent being in such quantity that two atoms thereof are introduced intothe phenyl radical.

2. A process for producing di-halogen substituted a- (p-hydroxyphenyl) a amino-acetic acid which comprises reacting upon u-(p-hy droxyphenyl)-a-amino-acetic acid with a halogenating agent in a weakly alkaline solution, said halogenating agent being in such quantity that two atoms thereof are introduced into the phenyl radical.

3. 3,5-diha1o-a- (p -hydroxyphenyl) -a-aminoacetic acid.

4. 3,5 di bromo 0c (p hydroxyphenyl) -ocamino-acetic acid, having the foimula and decomposing at 204 C. L

di-iodo-a- (p-hydro-Xyphenyl) flit-amino- 5. 3,5 acetic acid, having the formula CsH'IOsNIz, and decomposing at 207 C.

6. The processfor producing dihalogen substituted cc (p hydroxyphenyl) oz acetic acid o'r'ro DALMER. JOHN NIEMANN.

CERTIFICATE OF CORRECTION. Patent Noa 2,085,009; June 29, 1957.,

r oTTo DALNER, ET AL,-

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, second column, line 1+9, claim 6, for "acetic" read amino-acetic; and thatthe said Letters- Patent shouldbe read with this correction therein that the same may conform to the record of the case in the Patent OffiCeO Signed and sealed this 7th day of December A, D; 1957 r Henry Van Arsdale, I (S Acting Commissioner of Patents. 

